Relating to adverse Possession or similar kind.

Dear Sir/Ma'm My father(56) working as caretaker in a premises since last 25-27 years.He get this Job because he living in that building from at the age of 14-15 with her father and brother. The owner of the building appoint him as caretaker when he is 30-32 years old of that specific building and he got a small room below the stair for living. After my father's marrige, owner said my father that i want to meet your wife and children once because the owner very kind towards my father and he is no any son. when my mother went to meet with the owner, he accept to pay education expenses of my brother and sister and also said to my mother that i giving a another room for you to stay with your children because the area where this premises is situated is not good and the room which is given earlier is very small and open. after 2-3 years my father went to owner to get some for repairing the houses he said that i'm not going to pay any amount for that room because that is your , you have to manage their expenditure. And he said that I'm not going to make any agreement with because i don't want to allow you to sold it with any one , you stay their till your wish. then from that date he never talk any thing about that room. in year 2014 he dead. and after his dead that building and other assets going to manage by his daughter's husband . once daughter Husband asked us to give back(because some other one telling to him to asked for that) that room then after police complain and etc. he take back his wishes to take back that room. and after 1-2 years he surrender his ownership from entire building to rent controller. so finally after 2017 their is no any owner of the building. but some rich man who is tenant of the building try to make threat on us and indirectly try to make hostile possession on the another room which is given by the original/ first owner to my mother . i just need your advice that whether we have any right or not, my question is that if we want to give back that room then to whom i give .